Medical devices such as intravascular devices have been used to perform therapeutic procedures within a patient. For example, a medical device such as a distal protection wire may be used to navigate through the tortuous anatomy of a patient to reach an area of interest and protect the vasculature from potential loose emboli when other medical device are advanced thereto to perform one or more therapeutic procedures. A medical device may be introduced into a patient's anatomy or vasculature at a relatively accessible location such as a femoral or radial artery, and guided through the patient's anatomy to the desired location. Often, such medical devices are introduced in a delivery sheath. The medical device is frequently mounted on a distal portion of a wire such as a guidewire. The medical device fills and may completely occlude the deliver sheath lumen. Air may be trapped in the lumen of the delivery sheath proximal to the medical device. As this air may be released in the vasculature when the medical device is deployed, a flushing procedure is often used to replace this air with a liquid. This is time-consuming and may not expunge the air entirely. There is consequently an ongoing need to provide new and alternative methods of removing the air from catheters such as this delivery sheath.